subroutine set_external_event(lunit)
  use global_param,only:n_ext
  use global_param,only:extern_type
  use box_param,only:total_volume
  implicit none

  integer,intent(in) :: lunit

  integer :: i

  do i=1,n_ext
     extern_type(i)%max_n_occur=&
          extern_type(i)%dose/extern_type(i)%flux
     extern_type(i)%rate_const=extern_type(i)%flux*total_volume
     extern_type(i)%sdpa=0
     extern_type(i)%partial_sdpa=0
     extern_type(i)%dpa=0
     extern_type(i)%partial_dpa=0
  end do

  return

end subroutine set_external_event
